Question

using this:

defined('WPLANG')

I’m able to check whether the constant is defined or not, but how can I check the value of the constant to use it in an if statement?

Answer 1

define('WPLANG', 'some value');
if(WPLANG == 'some value'){
  ... 
  ...
}

Or

define('WPLANG', 1212);
if(WPLANG == 1212){
   ... 
   ...
}

It’s good to check if the constant is defined before checking its value, since if ( I_AM_UNDEFINED ) will always be false, because the value of an undefined constant is null. If you assume it exists and it doesn’t, then you could get some unexpected results. So:

if( defined('WPLANG') && WPLANG === 'some value' ) {